There's a discussion on the contra dance organizers list about attendance. Several organizers had noticed lower attendance lately, and were wondering if it was just their dance or if it was something shared. Here's what things look like for BIDA:

Update 2016-12-07: this is somewhat distorted by family dances, where we occasionally open the hall two hours early and do a family dance followed by a potluck before our regular dance. We've had ~4 of them, and they typically have higher attendance because they attract some people who wouldn't have come otherwise. Instead of trying to figure out what attendance would have been for those nights if we hadn't had the family portion, here's a version of the graph that excludes those evenings:

(I had already excluded "Spark in the Dark" dances.)

This is pretty positive; since the last time I looked at this we've moved from averaging ~100 to ~150, a large enough change that it's been over two years since we last had a dance with fewer than 100 dancers. So it looks like we're in decent shape.

(Right now what's awkward about the discussion is I suspect dances with recently lower attendance are much more likely to post because the discussion feels more relevant. And posting saying "our attendance is up" could even feel like bragging.)